2. The term ‘Data Logging' refers to collecting or gathering data
over a period of time.
A data logger is a device that can be used to store and retrieve
the data.
Data loggers capture, measure, and analyze physical
phenomena from the real world.
Light, temperature and pressure are examples of the different
types of signals that a Data logger can measure.
A data logger is often a hand-held battery operated device
which has a large amount of memory.
INTRODUCTION
3. How Data is Collected?
The objective of this work is to use data logging for
temperature measurement. In order to meet the above
requirements, a low cost, portable data logger is designed
A microcontroller based data logger has been developed for
measuring temperature at different input channels of ADC
Sensors are used to take readings or measurements at regular
intervals of their environment.
The sensors may be either analogue or digital. If they take
analogue readings, an Analogue to Digital Converter will be
needed to convert the signal into digital data which the
computer can understand.
4. As the sensor takes a reading, the data is sent though a cable or
wireless link to the data logger.
The device is designed to receive data from sensors and to store
the results on external non-volatile flash memory for post
process analysis.
An integrated Liquid crystal display (LCD) is also used for real
time display of data acquired from various sensors.
The sensors can be collected data on a wide range of things
such as temperature, humidity, pressure, wind speed, water
currents, electrical voltage, pH readings etc.
CONTINUED
5. • Dr. Saul Greenburg has described the concept of logging and
how logging is done is in detail, Logging is a process to record
events with the use of data loggers during a test or field use of a
system or a product
• Andrew Thompson, John L. Bahr and Neil Thomson have
described low cost, very low power consumption, self-
contained; digital data logger capable of independent operation
for long periods of time has been developed.
• Peter Roberson has reviewed the use of data loggers.
• H S kalsi has defined a data logger is a comprehensive and
highly advanced data acquisition system.
LITERATURE REVIEW
7. Building blocks of a data logger
Transducer or Sensors: A device that converts a physical
phenomenon such as light, temperature, pressure, or sound into a
measurable electrical signal such as voltage or current.
Analog to Digital Converter: The data logger senses only digital
signals and hence analog signals, it may converted to digital signal.
Microcontroller & Storage: Microcontroller is used to convert
digital signals into binary form, storage used to store the converted
digital signal.
Display: Some data loggers interface with a personal computer and
utilize software to activate the data logger and view and analyze the
collected data, while others have a local interface device (keypad,
LCD) and can be used as a stand-alone device.
8. Implementation and System Design
System Definition: Broad definition of system hardware including
microcontroller and its interface with display, ADC, memory, keypad etc.
Circuit Design: Selection of 8051 microcontroller and other
interfacing devices, as per system definition. Design of hardware
circuit and its testing on laboratory kits with some simple microcontroller
software routines.
PCB Design and Fabrication: Generation of schematic diagrams and
the production of circuit board layout data for the procurement of the
circuit board.
Software Design: Developing algorithm for the system, allocating
memory blocks as per functionality, coding and testing.
Integration and Final Testing: Integrating the entire hardware and
software modules and its final testing for data logging operation.
9. Stand Alone
Stand alone hardware can
continuously measure and log data
without connection to a PC.
Data Logger Topologies
PC Based
Operation requires full time
connection to a PC over any
appropriate bus technology.
10. Current Scenario
Nowadays, it is required to control the temperature,
pressure, humidity, displacement, etc. in a plant, hence
demand of data logger is increasing rapidly since it finds a
wide application in industries.
The cost of data loggers has been declining over the years
as technology improves and costs are reduced.
Simple single channel data loggers cost as little as $25.
More complicated loggers may costs hundreds or
thousands of dollars.
11. Future Aspects
Data Loggers are changing
more rapidly now than ever
before.
The original model of a stand
alone data logger is changing
to one of a device that
collects data but also has
access to wireless
communications for alarming
of events, automatic
reporting of data and remote
control.
Figure: Data Logger Application for
weather Station
12. ADVANTAGES
Data Logging can be used in remote or dangerous situations.
Data logging can be carried out 24 hours a day, 365 days of
the year.
Time intervals for collecting data can be very frequent and
regular, for example, hundreds of measurements per second.
No need to have a person present.
Data logging is often more accurate because there is no
likelihood of human error.
13. DISADVANTAGES
If the data logging equipment breaks down or malfunctions,
some data could be lost or not recorded.
Equipment can be expensive for small tasks.
The equipment will only take readings at the logging
interval which has been set up. If something unexpected
happens between recordings, the data will not be collected.
Data loggers typically have slower sample rates than Data
Acquisition System.
14. APPLICATIONS
They can be used in the following applications such as:
In unattended recording at weather stations to record parameters
like temperature, wind speed / direction, solar radiation and
relative humidity.
For hydrographic recording of water flow, water pH, water
conductivity, water level and water depth.
In the recording of soil moisture levels.
To record gas pressure and to monitor tank levels.
Vehicle Testing (including crash testing)
15. CONCLUSION
They are designed to operate continuously without interruption
even in the worst industrial environments.
It is a portable measurement instrument, has a wide application
in industries.
The digital data can be retrieved, viewed and evaluated after it
has been recorded.
Data loggers can be taken to diverse locations include:
mountains, deserts, jungles, mines, etc.
The specified accuracy is maintained throughout the period of
use.